Top layer for two applications in one

I have to rebuild an application that contains two main functionalities (administrating folders and groups). Both are totally different things, cannot be combined, and will be reconstructed with different design approaches.

My problem: Both functionalities / apps will be in the same web app in the end. I am now a little bit blocked, because I don't know how to build a top layer page above those two applications.

In the current app it is solved like this:

But I am not really happy about that. Does anybody have a good idea or an example where they have faced the same problem? Thanks in advance.